Disposable extrusion apparatus with pressure balancing modular die units for the production of nonwoven webs

Abstract

The present invention relates to a die body consisting of a multiplicity of modular die plates, which are easily and rapidly interchangeable. The modular die plates can be configured to extrude different shapes and types of fibers. The apparatus may also be configured to extrude multiple types of materials each from a plurality of separate ports or from a plurality of common ports. The apparatus may also be designed to include single or multiple ports to direct air or other fluids to draw or attenuate the extrudate into fibers of a desired diameter. The extrudate may be treated with the air or various other gases or fluids within the die or exterior to the die tips.

We claim: 
     
       1. A disposable modular extrusion die body for extruding fibers from molten, synthetic, thermoplastic, polymeric resins comprising; (a) a stack of alternating primary and secondary die plates;   (b) said primary and secondary die plate having :aligned top and bottom edges separated by no more than 0.15 meters;   (c) each of said primary and secondary die plates having a central opening there through, the central openings in said die plates communicating with each other to form a single continuous pressure equalization chamber within said die body extending through a central region of said die body;   (d) the top edge of each said primary die plate having an opening to receive molten polymeric resin, said opening communicating with said chamber permitting said polymeric resin to enter said chamber wherein each orifice is equidistant from the feed manifold;   (e) a top surface of said die body wherein the total area of the openings on said top surface is at least forty percent of the total area described by the width of the opening and length measured across all of the primary and secondary die plates;   (f) the bottom edge of each said secondary die plate having an extrusion slot extending to said chamber, the adjacent primary die plates forming with said extrusion slot an orifice for the extrusion of said polymer resin.   (g) a means for delivering a stream of fluid adjacent each said orifice comprising a passage way extending the length of said die body passing through all of said die plates, and a channel in each said secondary plate from said passageway to and terminating at the bottom edge of said secondary plate in a nozzle for delivering said fluid adjacent the extrude resin;   (h) an equalization chamber segment formed by and within each combination of adjacent primary and secondary plates which has a volume of at least 2,000 times and no more than 40,000 times the volume of the orifice:   (i) a means to maintain the multiplicity of modules in sealed alignment with each other.   
     
     
       2. The disposable modular extrusion die body of claim 1 wherein the secondary die plate has more than one shaped slot providing communication between the pressure equalization chamber to the lower plate edge and provides a series of lateral orifices equal in number to the number of slots. 
     
     
       3. The disposable modular extrusion die body of claim 1 in which said nozzles direct the stream of fluid at the extruded resin leaving said extrusion orifice. 
     
     
       4. The disposable modular extrusion die body of claim 1 wherein the primary plates and secondary plates have identical cross sections and where the primary plate is alternately reversed to act as a secondary plate. 
     
     
       5. The disposable modular extrusion die body of claim 1 wherein the width of the secondary plate is at least 0.001 inches and no greater than 0.200 inches. 
     
     
       6. The disposable modular extrusion die body of claim 1 where the primary and secondary plates have means for extruding multiple molten fluids consisting of different polymeric resins. 
     
     
       7. The disposable modular extrusion die body of claim 1 wherein the polymeric resins used have an apparent melt viscosity in the die tip ranging from about 500 poise to about 3000 poise. 
     
     
       8. The disposable modular extrusion die body of claim 1 where the primary and secondary plates are formed from steel, copper, aluminum, nickel, titanium and their various commercial alloys. 
     
     
       9. The disposable modular extrusion die body of claim 1 where the length of the die body is greater than 0.1 meters.